...

• PID: Process ID.
• USER: The owner of the process.
• PR: Process priority.
• NI: The nice value of the process.
• VIRT: Amount of virtual memory used by the process. On our servers, currently, the maximum virtual memory a job can use is 25% of the total memory. Which means 64 GB on most of our servers.
• RES: Amount of resident memory used by the process. This is the actual memory your process is using!!!
• SHR: Amount of shared memory used by the process.
• S: Status of the process. (See the list below for the values this field can take).
• %CPU: The share of CPU time used by the process since the last update. Can go up to a little more than 100%. When using shared memory parallelism (OpenMP) this value can go up to 100% times the number of shared memory processes.
• %MEM: The share of physical memory used.
• TIME+: Total CPU time used by the task in hundredths of a second[minutes:seconds].
• COMMAND: The command name or command line (name + options).

...

• D: Uninterruptible sleep
• R: Running
• S: Sleeping
• T: Traced (stopped)
• Z: Zombie

ps & kill

You can check which processes you have open with:
   

...

If you cannot find where you opened a process to close it down properly you can kill it with 'kill'. You only need to kill the master process. For example, if you get something like the following:

                  parent
UID          PID    PPID  C STIME TTY          TIME CMD
username 1460822       1  0 May23 ?        00:01:48 tmux
username  945179 1460822  0 May25 pts/20   00:00:00 -bash
username  945272  945179  0 May25 pts/20   00:37:36 /sca/.../jupyter-notebook --no-browser
username  969070  945272  0 May25 ?        00:10:16 /sca/.../python -m ipykernel_launcher -f /.../kernel-...json
username  987828  945272  0 May25 ?        00:09:37 /sca/.../python -m ipykernel_launcher -f /.../kernel-...json

In the example above, the PID (process ID) '1460822', is the main master process. It does not have a "parent", the PPID (parent process ID) is 1. This is the one you need to kill, then all it's "children", "grandchildren" and "great-grandchildren" etc. will get killed as well.
Note that processes are not always sorted in order!

Sometimes, it happens that processes do not have a parent anymore, then you need to kill them with their own PID.

The command to kill a process is:
 

So, for the example above:
    kill -9 1460822